There are techniques known in the art for determining the characteristics of target regions within an image based on image data representing the image. By correctly determining characteristics of the target regions, an image processor can perform image processing suited to these characteristics. According to one technology known in the art, an image processor divides an image into a plurality of blocks and calculates the contrast for each block. Subsequently, the image processor categorizes each block as a photograph, text, and the like based on their contrast.